Semiconductor device producing method

ABSTRACT

Disclosed is a producing method of a semiconductor device, including: loading at least one substrate formed on a surface thereof with a tungsten film into a processing chamber; and forming a silicon oxide film on the surface of the substrate which includes the tungsten film by alternately repeating following steps a plurality of times: supplying the processing chamber with a first reaction material including a silicon atom while heating the substrate at 400° C.; and supplying the processing chamber with hydrogen and water which is a second reaction material while heating the substrate at 400° C. at a ratio of the water with respect to the hydrogen of 2×10 −1  or lower.

This application is a Divisional of co-pending application Ser. No.11/990,451 filed on Feb. 14, 2008 and for which priority is claimedunder 35 U.S.C. §120. Application Ser. No. 11/990,451 is the nationalphase of PCT International Application No. PCT/JP2007/050571 filed onJan. 17, 2007 under 35 U.S.C. §371. Application Ser. No. 11/990,451claims priority under 35 U.S.C. §119(a) on Patent Application No.2006/008611 filed in Japan on Jan. 17, 2006. The entire contents of eachof the above-identified applications are hereby incorporated byreference.

The present invention relates to a producing method of a semiconductordevice, and for example, to a technique which is effective when an oxidefilm is formed on a semiconductor wafer which is one example of asubstrate to be processed by an ALD (Atomic Layer Deposition) method ora CVD (Chemical vapor deposition) method in a producing method of asemiconductor integrated circuit. Especially, the present inventionprovides a producing method of a semiconductor device for forming anoxide film on a substrate formed with a foundation metal film such as W(tungsten) while preventing the metal film from being oxidized.

In recent years, with density growth and multilayer wiring tendency insemiconductor devices, it is required to form an oxide film on afoundation metal film at a low temperature, and an oxide film materialwhich satisfies such a requirement is also required.

As a CVD oxide film forming method which satisfies the aboverequirement, a film forming (680 to 700° C.) using thermal decompositionof tetraethoxysilane (TEOS: Si (OC₂H₅)₄) has mainly been used. But thismethod needs to further low the temperature to prevent impurities frombeing again dispersed, and as an alternate method thereof, an oxide filmforming method (580 to 600° C.) using a combination of O₂ andbister-challis-butylaminosilane is also used.

As an oxide film forming method (400 to 500° C.) capable of forming anoxide film at a lower temperature, there are an oxide film formingmethod using a combination of O₂ and a material such as triethoxysilane(HSi (OC₂H₅)₃) and bismethylsililethane (H₂Si (CH₃)CH₂CH₂Si (CH₃)H₂),and an oxide film forming method using a combination of ozone (O₃) andtrisdimethylaminosilane (TDMAS:SiH[N(CH₃)₂]₃).

Recently, however, a metal film made of W and the like is frequentlyused as an electrode material, and if a metal film is used using theabove-described oxide film material, there is a problem that the metalfilm is oxidized.

It is, therefore, a main object of the present invention to provide aproducing method of a semiconductor device capable of forming an oxidefilm on a metal film at a low temperature while preventing a metal filmsuch as W from being oxidized.

According to one aspect of the present invention, there is provided aproducing method of a semiconductor device, comprising:

loading at least one substrate formed on a surface thereof with atungsten film into a processing chamber; and

forming a silicon oxide film on the surface of the substrate whichincludes the tungsten film by alternately repeating following steps aplurality of times: a step of supplying the processing chamber with afirst reaction material including a silicon atom while heating thesubstrate at 400° C.; and supplying the processing chamber with hydrogenand water which is a second reaction material while heating thesubstrate at 400° C. at a ratio of the water with respect to thehydrogen of 2×10⁻¹ or lower.

According to another aspect of the present invention, there is provideda producing method of a semiconductor device, comprising at least:

loading at least one substrate formed on a surface thereof with a metalfilm into a processing chamber; and

forming an oxide film including silicon on the surface of the substratewhich includes the metal film, wherein

forming the oxide film includes:

supplying a first reaction material including a silicon atom into theprocessing chamber while heating the substrate at a predeterminedtemperature; and

supplying hydrogen and a second reaction material including an oxygenatom into the processing chamber while heating the substrate at thepredetermined temperature.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a sectional view showing a schematic configuration of asemiconductor device according to preferred embodiments of the presentinvention;

FIG. 2 is a diagram showing a schematic configuration of a selectiveoxidizing device according to the preferred embodiments of the presentinvention;

FIG. 3 is a schematic diagram showing an oxidation-reduction region of Wand an oxidation-reduction region of Si with respect to a temperatureand a partial pressure of H₂O with respect to H₂;

FIG. 4 is a vertical sectional view showing a schematic configuration ofan ALD oxide film forming device according to the preferred embodimentsof the present invention;

FIG. 5 is a transverse sectional view showing a modification of the ALDoxide film forming device shown in FIG. 4;

FIG. 6 is a diagram showing a schematic sequence when an oxide film isformed using a normal ALD method;

FIG. 7 is a diagram showing a schematic sequence (A) when an oxide filmis formed on a W film in the preferred embodiments of the presentinvention;

FIG. 8 is a diagram showing a schematic modification of the sequence(A), and shows a sequence (B) when a catalyst is used;

FIG. 9 is a diagram showing a schematic modification of the sequence(A), and shows a sequence (C) when plasma excitation is used;

FIG. 10 is a perspective view showing a schematic configuration of asubstrate processing apparatus according to the preferred embodiments ofthe present invention; and

FIG. 11 is a diagram showing a modification of the semiconductor deviceshown in FIG. 1.

Preferred embodiments of the present invention will be explained belowwith reference to the drawings.

EMBODIMENT 1

First, an outline of the preferred embodiments of the present inventionwill be explained.

The present embodiments relate to a technique for forming an oxide filmincluding silicon on a surface of a substrate including a metal film. Inthe following description, a case in which a W (tungsten) film is usedas one example of the metal film, and a Si oxide film is formed on the Wfilm as one example of an oxide film including silicon will beexplained.

Concerning oxidization of the W film when H₂O (water) is used as oneexample of oxidizing material (oxidizer), it is conceived that theoxidation reaction proceeds by formation and separation of W oxide suchas WO₃H₂O and WO₃ by W and H₂O (equations (1) and (2)). Especially,since W is consumed and the W film is reduced by phenomenon of theequation (1), if an SiO film is formed thereon, the pattern performanceis deteriorated.

W+4H₂O=WO₃H₂O (gas)+3H₂  (1)

W+3H₂O=WO₃ (solid)+3H₂  (2)

In the reaction between W and H₂O, activation energy when WO₂ is formedis 5.9 eV, activation energy when WO₃ is formed is 4.7 eV, andactivation energy when WO₃H₂O is formed is 1.2 eV. Therefore, theequation (1) becomes a main reaction between W and H₂O.

A reaction equilibrium constant of the equation (1) can be expressed bythe equation (3). If the equation (3) is rewritten, the equation (3)becomes the equation (4).

K=(P_(WO3H2O))(P_(H2))³/(P_(H2O))⁴  (3)

P_(WO3H2O)=(P_(H2O))⁴/(P_(H2))³exp(−ΔG/kT)  (4)

In order to reduce oxidation of W from the equation (4), it is necessaryto reduce the partial pressure of H₂O, to increase the partial pressureof H₂ and to lower the film forming temperature.

Concerning oxidation of W film when O₃ (ozone) is used as anotherexample of the oxidizing material, it is conceived that W and O₃ form Woxide by reactions as shown in the following equations (5) to (8). Here,O₃ is decomposed into O₂ and active oxygen radical (0*) by heating asshown in the equation (5), and the active oxygen radical is adsorbed ona W surface to produce WO₃ as shown in the equation (6).

O₃=O₂+O  (5)

W+3O*=WO₃  (6)

If H₂ is supplied to W and active oxygen radical, the active oxygenradical and H₂ produce H₂O as shown in the equation (7), and W and H₂Oproduce W oxide as shown in the equation (8). As a result, if H₂ issupplied to W and active oxygen radical, the equation (8) that is thesame as the equation (1) is derived.

W+O*+H₂=W+H₂O  (7)

W+4H₂O=WO₃[H₂O] (gas))+3H₂  (8)

Usually, since H₂ concentration is greater than O₃ concentration, H₂Oconcentration produced in the equation (7) depends on O₃ concentration.

The reaction equilibrium constant in the equation (8) is expressed bythe equation (9) that is the same as the equation (3). If the equation(9) is rewritten, the equation (9) becomes the equation (10) that is thesame as the equation (4).

K=(P_(WO3H2))(P_(H2))³/(P_(H2O))⁴  (9)

P_(WO3H2O)=(P_(H2)O)⁴/(P_(H2))³exp(−ΔG/kT)  (10)

When O₃ is used as the oxidizing material, like the case where H₂O isused, in order to reduce oxidation of W from the equation (10), it isnecessary to reduce the partial pressure of H₂O, to increase the partialpressure of H₂ and to lower the film forming temperature.

From the equations (4) and (10), when a partial pressure of H₂O isincreased while setting a partial pressure of H₂ to be constant, theoxidation amount of W is increased. On the contrary, when the partialpressure of H₂ is increased while setting the partial pressure of H₂O tobe constant, the oxidation amount of W is reduced. Thus, the oxidationamount of W depends on partial pressures of H₂O (or O₃) and H₂.

In the preferred embodiments of the present invention, when alternatelysupplying a Si material and an oxidizing material such as H₂O (or O₃)onto W, in order to prevent W from being oxidized by H₂O (or O₃), H₂ issupplied as the same time as H₂O (or O₃) is supplied to reduce thepartial pressure of H₂O. This makes it possible to oxidize the Simaterial by H₂O (or O₃) while preventing W from being oxidized.

Since a partial pressure ratio of H₂O (or O₃) to H₂ is substantially thesame as a supply ratio thereof, it may be conceived that the “partialpressure ratio” and a “supply ratio” are the same.

Next, a semiconductor device according to the preferred embodiments ofthe present invention will be explained with reference to FIG. 1.

FIG. 1 is a sectional view showing a schematic configuration of thesemiconductor device according to the preferred embodiments of thepresent invention, and more particularly shows one example of thesemiconductor device which is a tip device in which MPU/ASIC metal halfpitch is more than 65 nm, and which forms a Si oxide film by an ALDmethod.

A semiconductor device 15 includes a Si substrate 20, and a SiO₂ layer21 is embedded in a surface area of the Si substrate 20. A SiO₂ region22 for separating devices is formed on a Si layer 23 on the SiO₂ layer21, and a plurality of device regions 16 are formed between the SiO₂regions 22. Each device region 16 is formed with source regions 24 and25 and drain regions 27 and 26. A gate oxide film 28 is formed on asurface of the Si layer 23 between the source region 25 and the drainregion 26.

A gate electrode 31 is formed on the gate oxide film 28. The gateelectrode 31 comprises a W film 30. An SiO film 32 and an SiN film 33 assidewalls are formed in this order on a side surface of the gateelectrode 31. The source region 25 of low concentration and the drainregion 26 of low concentration are formed on the gate electrode 31 in aself-aligning manner. The source region 24 of high concentration and thedrain region 27 of high concentration are formed on the SiO film 32 andthe SiN film 33 in the self-aligning manner. In the semiconductor device15, the MOS transistor 17 having the gate oxide film 28, the gateelectrode 31, the source regions 24 and 25 and the drain regions 27 and26 is formed in each device region 16.

When polycide (WSix/PolySi) in which oxidation does not cause a problemis used as constituent material of the gate electrode 31, the SiO film32 and the SiN film 33 as sidewalls are formed by the CVD method at 680°C. and 700° C., respectively, but since PolySi electrode deterioratesthe driving force due to depletion, a metal gate (W film 30) is used asthe gate electrode as described above in the generation after MPU/ASICmetal half pitch 65 nm such as the semiconductor device 15.

If the SiN film 33 is formed directly on the side surface of the gateelectrode 31, junction capacitance is generated. Therefore, it isgeneral to insulate the side surface of the gate electrode 31 by the SiOfilm 32 as the device structure becomes smaller in size like thesemiconductor device 15 of the embodiment. Further, in order to reducethe junction capacitance or leak current, there is a tendency thatinsulation material such as SOI (Silicon On Insulator) is used for alower layer of the Si substrate 20.

An SiN layer 34 which becomes an etching stopper is formed on the entiresurface of a surface of the Si substrate 20 formed with the MOStransistor 17. An SiO₂ film 35 which becomes an interlayer isolationfilm is formed on the SiN layer 34. The SiN layer 34 and the SiO₂ film35 are formed with a via hole 36 through which the source region 24 andthe drain region 27 of the MOS transistor 17 are exposed. Wiring metals37 extends through the via holes 36 at portions from the source region24 and the drain region 27 to an upper surface of the SiO₂ film 35.

SiN layers 38 are formed on the entire surface of an upper surface ofthe SiO₂ film 35 such as to cover the wiring metal 37 exposed from theSiO₂ film 35. A porous layer 39 having a low dielectric constant isformed on the SiN layer 38, and an SiO₂ layer 40 is provided on theporous layer 39. An interlayer isolation film comprising the porouslayer 39 and the SiO₂ layer 40 is formed with a via hole 41. A wiringmetal 42 is embedded in the via hole 41. Thereafter, a plurality ofinterlayer isolation films each comprising the porous layer 39 and theSiO₂ layer 40 are laminated on one another through the SiN layers 38,and the wiring metal 42 penetrates each layer.

According to the semiconductor device 15, the SiO film 32 and the SiNfilm 33 are sequentially formed after the W film 30 is formed, but ifthe W film 30 is oxidized when forming the SiO film 32, there arises aproblem that a shape thereof is varied due to volume expansion caused bythe oxidation of W. Therefore, in the preferred embodiments of thepresent invention, the SiO film 32 is formed on the W film 30 by the ALDmethod while preventing the W film 30 from being oxidized.

Next, a selective oxidizing device which is reviewed for realizing thepreferred embodiments of the present invention will be explained withreference to FIG. 2.

FIG. 2 is a diagram showing a schematic configuration of the selectiveoxidizing device according to the preferred embodiments of the presentinvention, and shows a schematic configuration for selectively oxidizingSi while preventing W from being oxidized in a semiconductor devicewhere Si and W exist on a wafer surface at the same time.

The selective oxidizing device 50 mainly includes a gas supply mechanism60, a catalyst type moisture generating device (CWVG) 70, a processingfurnace 80 and a load lock chamber 90. The gas supply mechanism 60 isprovided with gas supply pipes 61 to 65 for N2, H₂ and O₂. The supplypipes 62 to 65 are provided with valves 62 a to 65 a and mass flowcontrollers 62 b to 65 b, respectively, so that it is possible to supplygases, stop the supply and adjust the flow rate by opening and closingthe valves 62 a to 65 a, and by controlling the mass flow controllers 62b to 65 b. The supply pipe 61 for N2 is connected to the supply pipes 62to 64 so that gases in the supply pipes 62 to 64 can be purged.

The CWVG 70 includes a reactor 71 which produces H₂O from H₂ and O₂ by acatalyst. The supply pipe 62 for H₂ and the supply pipe 63 for O₂ areconnected to each other to form a supply pipe 66, and the supply pipe 66is connected to one side of the reactor 71. A supply pipe 73 forsupplying H₂O produced by the reactor 71 to the processing furnace 80 isconnected to the other side of the reactor 71. Heaters 73 to 75 areprovided at intermediate portions of the supply pipe 66 and the supplypipe 73 so that gases flowing through the supply pipe 66 and the supplypipe 73 can be heated. The supply pipe 64 for H₂ is connected to thesupply pipe 73.

The processing furnace 80 constitutes a processing chamber in whichwafers are processed. A boat 82 on which a large number of wafers 81 areplaced is accommodated in the processing furnace 80. A nozzle 83extending along a sidewall is provided inside the processing furnace 80.The nozzle 83 is connected to the supply pipe 73, the nozzle 83 receivesgas supply from the supply pipe 73, and the gas is supplied into theprocessing furnace 80. A discharge pipe 84 is connected to theprocessing furnace 80 so that unnecessary excessive gas in theprocessing furnace 80 can be exhausted. The heater 85 is providedoutside the processing furnace 80 so that inside of the processingfurnace 80 can be heated.

The load lock chamber 90 is provided below the processing furnace 80. Agate valve 91 is provided at an upper portion in the load lock chamber90, and the boat 82 can be vertically moved between the processingfurnace 80 and the load lock chamber 90 through a gate valve 91. A gatevalve 92 is provided also on the side of the load lock chamber 90, andthe boat 82 can be brought into and out from the load lock chamber 90between inside and outside the load lock chamber 90 through the gatevalve 92. The supply pipe 65 for N2 is in communication with the loadlock chamber 90 so that inside of the load lock chamber 90 can bebrought into N2 atmosphere. A discharge pipe 94 connected to a vacuumpump 93 is connected to the load lock chamber 90. A valve 95 is providedat an intermediate portion of the discharge pipe 94, and if the vacuumpump 93 is operated in a state where the valve 95 is opened, the loadlock chamber 90 can be evacuated.

According to the selective oxidizing device 50, H₂ and O₂ can besupplied to the reactor 71 through the supply pipes 62, 63 and 66 togenerate H₂O, and H₂ can be supplied to a supply pipe 72 through thesupply pipe 64. In a state where H₂O and H₂ are mixed, the mixture isallowed to flow into the processing furnace 80 from the supply pipe 72through the nozzle 83, H₂O and H₂ are supplied to wafers 81, and Si isselectively oxidized while preventing W from being oxidized.

Next, a principle for forming an oxide film on a W film while preventingthe W film from being oxidized will be explained with reference to FIG.3.

FIG. 3 is a schematic diagram showing an oxidation-reduction region of Wand an oxidation-reduction region of Si with respect to a temperatureand a partial pressure of H₂O with respect to H₂.

When H₂O is used as one example of the oxidizing material, oxidation ofW proceeds in a region where the partial pressure of H₂O is high, SiO₂is reduced in a region where a temperature is high, and reduction of WO₃and oxidation of Si proceed at the same time in an intermediate regionthereof. The oxidation speed of Si is increased together with thepartial pressure of H₂O and the thickness of the oxide film isincreased.

At temperature in a range of 100 to 450° C., if a partial pressure ratioof H₂O with respect to H₂ is equal to or lower than a curve (a boundaryline between oxidation and reduction) shown with a reference number 400in FIG. 3, it can be found from FIG. 3 that WO₃ is reduced and it ispossible to prevent W from being oxidized. More specifically, if atemperature and a partial pressure ratio of H₂O with respect to H₂ aredenoted by (T(° C.), H₂O/H₂), (T(° C.), H₂O/H₂)=(100° C., 8×10⁻⁴), (200°C., 2×10⁻²), (300° C., 9×10⁻²), (400° C., 2×10⁻¹) and (450° C.,2.5×10⁻¹). If the partial pressure ratio of H₂O with respect to H₂ attemperature in a range of 100 to 450° C. is equal to or less thanstraight lines connecting these points (straight lines shown with areference number 500 in FIG. 3), it can be found that it is possible toreduce WO₃ and to prevent W from being oxidized.

For example, if the temperature is 400° C. and the partial pressureratio of H₂O with respect to H₂ is equal to or less than 2×10⁻¹, WO₃ isreduced and it is possible to prevent W from being oxidized.

In order to oxidize Si while preventing W from being oxidized, it isnecessary that the lower limit value of the temperature is set to 100°C. The reason why the lower limit value is set to 100° C. is that if thevalue is less than 100° C., the oxidation ability of H₂O with respect toSi is lost or reduced.

When O₃ is used as another example of the oxidizing material, undersufficient H₂ atmosphere, H₂O is produced from O₃ as shown in theequations (11) and (12) at a low temperature of 450° C. or less, and H₂Ois produced from O₃ as shown in the equations (13) and (14) also at alow temperature of higher than 450° C. Like the case where H₂O is usedas one example of the oxidizing material, reduction of WO₃ and oxidationof Si are expressed with the partial pressure of H₂O.

O₃=O₂+O*  (11)

O*+H₂=H₂O  (12)

O₃=3O*  (13)

3O*+3H₂=3H₂O  (14)

However, when O₃ is used as another example of the oxidizing material, 1mole oxygen radical is produced with respect to 1 mole O₃ (see equation(11)) at a low temperature of 450° C. or less, whereas 3 moles oxygenradical is produced with respect to 1 mole O₃ at a high temperature ofhigher than 450° C. (see equation (13)). Thus, the fact that the H₂Oconcentration is varied between the low temperature range and hightemperature range should be taken into account.

When O₃ is used as the oxidizing material at a low processingtemperature of 450° C. or less, since 1 mole H₂O is produced from 1 moleO₃ (thermal decomposition of O₃ at 400° C. is 99.9%) based on theequations (11) and (12), even if O₃ is used as the oxidizing material,it can be conceived that O₃ is equal to H₂O as the oxidizing material,and it can also be conceived that a relation between the temperature andthe partial pressure ratio of O₃ with respect to H₂ is equal to arelation between the temperature and the partial pressure ratio of H₂Owith respect to H₂.

Next, an ALD oxide film forming device according to the preferredembodiments of the present invention will be explained with reference toFIG. 4.

FIG. 4 is a vertical sectional view showing a schematic configuration ofthe ALD oxide film forming device according to preferred embodiments ofthe present invention.

The ALD oxide film forming device 202 includes a load lock chamber 300.The load lock chamber 300 is provided at its upper portion with aprocessing furnace 304 through a manifold 302 and an O-ring 303. Theboat 312 on which the plurality of wafers 310 are placed is accommodatedin the processing furnace 304, and W films are formed on surfaces of thewafers 310. The boat 312 is rotatably supported by a seal cap 314. Theseal cap 314 is in intimate contact with a flange portion of themanifold 302 through the O-ring 316, and a lower portion of theprocessing furnace 304 is closed. In the ALD oxide film forming device202, a processing chamber 318 which processes the wafers 310 is formedby at least the seal cap 314, the O-ring 316, the manifold 302, theO-ring 303 and the processing furnace 304.

The processing furnace 304 is provided with nozzles 320 and 324. Thenozzles 320 and 322 extend along an inner wall of the processing furnace304, and a large number of supply holes 322 and 326 are provided atintermediate portions of the nozzles. Si material (e.g., TDMAS) flowsinto the nozzles 320, and the Si material can be supplied to theprocessing chamber 318 from the supply hole 322. The oxidizing material(e.g., H₂O or O₃) can flow into the nozzle 324, and the oxidizingmaterial can be supplied to the processing chamber 318 from the supplyhole 326.

A discharge pipe 330 is connected to the manifold 302 so that gas in theprocessing furnace 304 can be exhausted. A heater 340 is providedoutside the processing furnace 304 so that the processing chamber 318can be heated.

According to the ALD oxide film forming device 202, basically, a Simaterial and an oxidizing material such as H₂O are alternately suppliedto the processing chamber 318 through the nozzles 320 and 324 repeatedlya plurality of times while heating the processing chamber 318 by theheater 340, and Si oxide films can be formed on the W films of thewafers 310. Especially in this embodiment, when the oxidizing materialis supplied through the nozzle 324, H₂ is also supplied at the sametime, and Si oxide film are formed while preventing the W film frombeing oxidized.

When H₂O is used as the oxidizing material, if the supply pipe 72 of theselective oxidizing device 50 is connected to the nozzle 324, H₂O and H₂can be supplied to the processing chamber 318 at the same time.

As shown in FIG. 3, when the wafers 310 in the processing chamber 318are heated at a low temperature of 400° C. by the heater 340, it isnecessary that the partial pressure ratio of H₂O with respect to H₂ isset to 2×10⁻¹ or lower to prevent the W film on the wafer 310 from beingoxidized.

Further, O₂ and O₃ can also be used as the oxidizing material inaddition to H₂O. This is because that if O₂ and O₃ are supplied togetherwith H2 at the same time, O₂ and O₃ can react with H₂ and H₂O can beproduced. When O₂ is used as the oxidizing material, it is necessarythat the temperature in the processing chamber 318 is increased to atleast 500° C. or higher to react with the H₂, but if O₃ is used as theoxidizing material, it is possible to produce the same at a lowtemperature (see equations (11) and (12)).

A catalyst such as pyridine (CAS No. 110-86-1, C₅H₅N, molecular weight79.1) may be supplied into the processing chamber 318 together with theSi material from the nozzle 320 to form an Si oxide film, or a catalystsuch as pyridine may be supplied into the processing chamber 318together with the Si material and H₂O to form an Si oxide film.

A device for generating plasma may be used as another example of the ALDoxide film forming device, and H₂O may be generated by H₂ andplasma-excited O₂.

One example of the ALD oxide film forming device capable of generatingplasma which is a modification of the ALD oxide film forming deviceshown in FIG. 4 will be shown with reference to FIG. 5.

The processing furnace 304 is provided with a nozzle 114 through whichO₂ is supplied to the processing chamber 318. The nozzle 114 extendsalong the inner wall of the processing furnace 304, and a large numberof supply holes 211 are formed at an intermediate portion thereof. Theprocessing furnace 304 is provided with a pair of electrodes 230 and 231and covers 218 and 220 for protecting the electrodes. The electrodes 230and 231 and the covers 218 and 220 also extend along the inner wall ofthe processing furnace 304, and the electrodes 230 and 231 are insertedthrough the covers 218 and 220.

A variable capacitor 232 and an AC power supply 233 are provided betweenthe electrodes 230 and 231. A control device 9 is connected to thevariable capacitor 232 and the AC power supply 233.

The processing furnace 304 is provided with a diaphragm 212 such as tosurround the nozzle 114, the electrodes 230 and 231 and the covers 218and 220. The diaphragm 212 stands along the inner wall of the processingfurnace 304 to form a supply hole 238 like the nozzle 114.

According to the above-described ALD oxide film forming device 202, ifvoltage is applied between the electrodes 230 and 231, plasma can begenerated in a region surrounded by the diaphragm 212 and the inner wallof the processing furnace 304. In this case, if O₂ is supplied to theprocessing furnace 304 through the nozzle 114, oxidation radical isproduced, the oxygen radical is supplied to the processing chamber 318through the supply hole 238 of the diaphragm 212, and H₂O can begenerated in the processing chamber 318.

At the same time when O₂ is supplied, inert gas such as Ar and N2 may besupplied to the processing furnace 304.

Next, a forming method of an oxide film according to the preferredembodiments of the present invention using the ALD oxide film formingdevice will be explained with reference to FIGS. 6 to 9.

A process sequence of the Si oxide film by a normal ALD method will beexplained with reference to FIG. 6.

Before the Si oxide film is formed, a plurality of wafers 310 arebrought into the processing chamber 318 from the load lock chamber 300in a state where the wafers 310 formed with W films are placed on theboat 312, and the processing of cycle shown in FIG. 6 is repeatedlyexecuted. One cycle mainly includes four steps.

In the first step, the wafers 310 in the processing chamber 318 areheated to a predetermined temperature, the Si material is supplied intothe processing chamber 318 from the nozzle 320 and the material isadsorbed on the surfaces of the wafers 310.

In the second step, the inside of the processing chamber 318 is purgedby inert gas, the Si material remaining in the processing chamber 318 isexhausted from the processing chamber 318 through the discharge pipe330.

In the third step, the wafers 310 in the processing chamber 318 areheated to substantially the same temperature as that in the first step,the oxidizing material (e.g., H₂O or O₃) is supplied into the processingchamber 318 from the nozzle 324, and the Si material adsorbed on thesurfaces of the wafers 310 and the oxidizing material are reacted witheach other to form Si oxide films.

In the fourth step, the inside of the processing chamber 318 is purgedby inert gas, and oxidizing material remaining in the processing chamber318 is exhausted from the processing chamber 318 through the dischargepipe 330.

The processing time in the first step (Si material supplying step) is 1to 30 seconds, the processing time in the is the second step (purgestep) is 5 to 15 seconds, the processing time in the third step(oxidizing material supplying step) is 5 to 60 seconds, and theprocessing time in the fourth step (purge step) is 3 seconds.

The processing operations in the first to fourth steps are executedwhile controlling the timing of supply and discharge of the processinggas (Si material gas, oxidizing material gas), the pressure in theprocessing chamber 318 and the operation of the heater 340.

In the preferred embodiment of the present invention, the followingsequences (A) to (C) are employed.

Concretely, in the sequences (A), as shown in FIG. 7, the first, secondand fourth steps are the same as the ALD oxide film forming step in FIG.6. In the third step, H₂ and the oxidizing material (e.g., H₂O or O₃)are supplied into the processing chamber 318 from the nozzle 324 at thesame time.

Especially in the sequence (A), in the third step, the heatingtemperature of the processing chamber 318 and a supply ratio of H₂O arecontrolled so as to prevent the W films from being oxidized. That is, inFIG. 3, the heating temperature of the processing chamber 318 and thesupply ratio of H₂O with respect to H₂ are controlled such that a regionwhere WO₃ is reduced is selected.

For example, when H₂O is supplied as the oxidizing material whileheating the processing chamber 318 at 400° C., the supply ratio of H₂Owith respect to H₂ is set to 2×10⁻¹ or less. When the processing chamber318 is heated within a range of 100 to 450° C., the supply ratio of H₂Owith respect to H₂ is set to a curve shown with a symbol 400 in FIG. 3or less (straight line shown with a symbol 500 in FIG. 3 or less). As aresult, even if the W film is oxidized in the sequence (A), the oxide isreduced, the Si material is oxidized even at a low temperature as low as450° C. or less, and it is possible to form a Si oxide film on the Wfilm at a low temperature as low as 450° C. or less.

Also when O₃ is supplied as the oxidizing material while heating theprocessing chamber 318 at temperature in a range of 100 to 450° C., ifthe supply ratio of O₃ with respect to H₂ is handled as the supply ratioof H₂O with respect to H₂, it is possible to form an Si oxide film onthe W film at a low temperature as low as 450° C. or less whilepreventing the W film from being oxidized.

In the sequence (B) which is a modification of the sequence (A), asshown in FIG. 8, the first to fourth steps are basically the same as thesteps in the sequence (A), and especially in the third step, a catalystis supplied to the processing chamber 318 in addition to the oxidizingmaterial (e.g., H₂O) and H₂. As the catalyst, a material such as thepyridine can be used. With such a catalyst, it is possible to easilyform a Si oxide film at a low temperature as low as 450° C. or less.

In the sequence (B), a catalyst such as the pyridine can be supplied tothe processing chamber 318 in addition to the Si material also in thefirst step.

In the sequence (C) which is a modification of the sequence (A), thefirst to fourth steps are basically the same as the steps in thesequence (A). Especially, ALD oxide film forming device capable ofgenerating plasma as shown in FIG. 5 is used, O₂ is used as an oxidizingmaterial, and plasma-excited O₂ and non-excited H₂ are supplied into theprocessing chamber 318 at the same time in the third step.

It is an object of the preferred embodiments of the present invention toform an oxide film at a low temperature while preventing W from beingoxidized. Therefore, the oxide film may be formed without supplying H₂after the oxide film is formed until a desired thickness at which W isnot oxidized is obtained. In this case, the productivity (film formingspeed) of the oxide film can be enhanced.

That is, an oxide film is formed while supplying an oxidizing materialand H₂ complying with the sequences (A) and (C) until a desiredthickness at which it is conceived that W is not oxidized is obtained,and if the thickness reaches a value at which W is not oxidized, H₂ isnot supplied thereafter, and the film forming manner is switched to thenormal ALD method complying with the sequence in FIG. 6. The “normal ALDmethod” mentioned here is a method in which a Si oxide film is formedwhile alternately supplying a Si material and an oxidizing material aplurality of times in a state where H₂ is not supplied.

A relation between a film thickness of an oxide film formed on W and anoxidizing material which passes through the oxide film and oxidizes Wcan be obtained by calculating a diffusion constant in oxygen in theoxide film.

In this embodiment, a film thickness X₀ at which it is possible to avoidoxidation of W is expressed by the equation (15) complying with a linerule.

X ₀ =B/A×t  (15)

[B/A]=Ce^(−E2/kT), [C]=18.35 Å/second, [E₂]=7.5×10⁻² eV, [k] is aBoltzmann constant and k=8.62×10⁻⁵ eVK⁻¹, and [t] is supply time(oxidation time) of O₃.

For example, when an Si oxide film is to be formed using O₃ whileheating the processing chamber 318 to 300° C., a value of K is273+300=573 (K), and a value B/A can be calculated as about 4.01Å/second. If the supply time of O₃ is 5 seconds, a value X₀ can becalculated as about 20 Å. Since a film thickness per one layer Si oxidefilm is about 0.7 Å, if the Si oxide films are laminated by 29 layers,the film thickness of the Si oxide film reaches 20 Å, and it isconceived that oxidation of W by O₃ can be avoided.

Therefore, in this case, an Si oxide film is formed by the ALD method inwhich O₃ and H₂ are supplied until the Si oxide films are laminated by29 layers and the film thickness reaches 20 Å, and after the filmthickness reaches 20 Å, in the supply step of O₃ and H₂, H₂ is notsupplied and the Si oxide film may be formed by the normal ALD method.As a result, the productivity (film forming speed) of Si oxide film canbe enhanced.

Next, a substrate processing apparatus according to the preferredembodiments of the present invention will be explained with reference toFIG. 10.

The substrate processing apparatus is constituted as one example of asemiconductor producing apparatus which carries out processing steps ina producing method of a semiconductor device (IC (Integrated Circuit)).A case in which a vertical type apparatus which subjects substrates tooxidation processing will be explained as one example of the substrateprocessing apparatus in the following description.

FIG. 10 is a perspective view showing a schematic configuration of thesubstrate processing apparatus according to the preferred embodiments ofthe present invention.

A processing apparatus 101 uses wafers 200 made of silicon as oneexample of substrates, and uses cassettes 110 as wafer carriers whichaccommodate the wafers 200. The processing apparatus 101 includes acasing 111 having a front wall 111 a. A front maintenance opening 103 asan opening is formed at a lower portion of the front wall 111 a so thatmaintenance can be carried out. A front maintenance door 104 is providedfor opening and closing the front maintenance opening 103.

A cassette carry in/out opening 112 is formed at the maintenance door104 so that an inside and an outside of the casing 111 are incommunication through the cassette carry in/out opening 112. Thecassette carry in/out opening 112 is opened and closed by a frontshutter 113.

A cassette stage 114 is disposed at the cassette carry in/out opening112 inside the casing 111. The cassette 110 is transferred onto thecassette stage 114 by a rail guided vehicle (not shown) and carried outfrom the cassette stage 114. The cassette 110 delivered by the railguided vehicle is placed on the cassette stage 114 such that the wafers200 in the cassette 110 are in their vertical attitudes and a waferin/out opening of the cassette 110 is directed upward.

Cassette shelves 105 are disposed substantially at a central portion inthe casing 111 in its longitudinal direction, and the cassette shelves105 store a plurality of cassettes 110 in a plurality of rows and aplurality of lines. The cassette shelves 105 are provided with transfershelves 123 in which the cassettes 110 to be transferred by a waferloading mechanism 125 are to be accommodated. Buffer cassette shelves107 are provided above the cassette stage 114 to subsidiarily store thecassettes 110.

A cassette transfer device 118 is provided between the cassette stage114 and the cassette shelves 105. The cassette transfer device 118includes a cassette elevator 118 a capable of vertically moving whileholding the cassette 110, and a cassette transfer mechanism 118 b as atransfer mechanism. The cassette transfer device 118 transfers thecassette 110 between the cassette stage 114, the cassette shelves 105and the auxiliary cassette shelves 107 by a continuous motion of thecassette elevator 118 a and the cassette transfer mechanism 118 b.

A wafer loading mechanism 125 is provided behind the cassette shelves105. The wafer loading mechanism 125 includes a wafer loading device 125a which can rotate or straightly move the wafer 200 in the horizontaldirection, and a wafer loading device elevator (not shown) whichvertically moves the wafer loading device 125 a. The wafer loadingdevice elevator is provided on a right end of the pressure-proof casing111. Tweezers 125 c of the wafer loading device 125 a as a placingportion of the wafers 200 charges a boat 217 with wafers 200 anddischarges the wafers 200 from the boat 217 by continuous motion of thewafer loading device elevator and the wafer loading device 125 a.

A clean unit 134 a for supplying clean air which is a purifiedatmosphere is provided behind the buffer shelves 107. The clean unit 134a includes a dustproof filter and a supply fan so that the clean airflows into the casing 111.

A clean unit (not shown) for supplying clean air is provided on a rightside of the casing 111, i.e. on the opposite side of the wafer loadingdevice elevator. The clean unit includes a supply fan and a dustprooffilter as with the clean unit 134 a. Clean air supplied from the cleanunit flows through near the wafer loading device 125 a and the boat 217,and then is exhausted outside the casing 111.

A pressure-proof casing 140 is disposed behind a wafer loading device125 a. The pressure-proof casing 140 has a hermetic structure capable ofmaintaining a pressure lower than atmospheric pressure (negativepressure). The pressure-proof casing 140 forms a load lock chamber 141which is a load lock type standby chamber having a capacity capable ofaccommodating the boat 217.

A wafer transfer in/out opening 142 is formed in a front wall 140 a ofthe pressure-proof casing 140. The wafer transfer in/out opening 142 isopened and closed by a gate valve 143. A gas supply pipe 144 throughwhich an inert gas such as nitrogen gas is supplied to the load lockchamber 141 and a discharge pipe (not shown) through which gas in theload lock chamber 141 is exhausted while keeping a negative pressure inthe load lock chamber 141 are connected to a sidewall of thepressure-proof casing 140.

A processing furnace 202 is provided above the load lock chamber 141. Alow end of the processing furnace 202 is opened and closed by a furnaceopening gate valve 147.

As schematically shown in FIG. 10, a boat elevator 115 for verticallymoving the boat 217 is disposed in the load lock chamber 141. An arm(not shown) as a connecting tool is connected to the boat elevator 115.A seal cap 219 as a lid is horizontally connected to the arm. The sealcap 219 vertically supports the boat 217, and the seal cap 219 can closethe lower end of the processing furnace 202.

The boat 217 includes a plurality of holding members. In a state where aplurality of (e.g., about 50 to 150) wafers 200 are arranged in thevertical direction such that their centers are aligned with each other,the boat 217 horizontally holds the wafers 200.

Next, the operation of the substrate processing apparatus 101 will beexplained.

Before a cassette 110 is supplied to the cassette stage 114, a cassetteloading/unloading opening 112 is opened by a front shutter 113. Then,the cassette 110 is loaded into the cassette stage 114 from the cassettetransfer in/out opening 112. At that time, the wafers 200 in thecassette 110 are held in their vertical attitudes, and the cassette 110is disposed such that a wafer in/out opening of the cassette 110 isdirected upward.

Next, the cassette 110 is lifted up from the cassette stage 114 by thecassette transfer device 118, the cassette 110 is rotated clockwisely inthe vertical direction by 90° such that the wafers 200 in the cassette110 are in their horizontal attitudes, and the wafer in/out opening ofthe cassette 110 is directed rearward of the casing 111. Next, thecassette 110 is automatically transferred to a designated shelf positionof the cassette shelves 105 or the buffer shelves 107 by the cassettetransfer device 118, the cassette 110 is delivered and temporarilystored and then, the cassette 110 is transferred to the cassette shelves105 by the cassette transfer device 118 or directly transferred to thecassette shelves 105.

Then, a slide stage 106 horizontally moves the cassette shelves 105, andpositions the cassette 110 which is to be loaded such that the cassette110 is opposed to the wafer loading device 125 a. The waferloading/unloading opening 142 of the load lock chamber 141 whosepressure is previously set equal to the atmospheric pressure is openedby the operation of the gate valve 143, the wafers 200 are picked up bytweezers 125 c of the wafer loading device 125 a through the waferin/out opening, the wafers 200 are loaded into the load lock chamber 141through the wafer loading/unloading opening 142, the wafers 200 aretransferred to the boat 217, and the boat 217 is charged with wafers200. The wafer loading device 125 a which delivered the wafers 200 tothe boat 217 returns to the cassette 110, and charges the boat 217 withthe next wafers 200.

When the boat 217 is charged with a predetermined number of wafers 200,the wafer transfer in/out opening 142 is closed by the gate valve 143,and the load lock chamber 141 is evacuated. If the pressure in the loadlock chamber 141 is reduced to the same level as that in the processingfurnace 202, a lower end of the processing furnace 202 is opened by thefurnace opening gate valve 147. Then, the seal cap 219 is moved upwardby the boat elevator 115, and the boat 217 supported by the seal cap 219is loaded into the processing furnace 202.

After the loading, the processing furnace 202 subjects the wafers 200 toarbitrary processing (the above-described forming processing of Si oxidefilm). After the processing, the boat 217 is pulled out by the boatelevator 115, the pressure in the load lock chamber 140 is returned tothe atmospheric pressure and then, the gate valve 143 is opened.Thereafter, the cassette 110 and the wafers 200 are unloaded outside thecasing 111 by reversing the above-described procedure.

EMBODIMENT 2

Next, a modification of the semiconductor device according to thepreferred embodiments of the present invention will be explained withreference to FIG. 11.

FIG. 11 is a diagram showing a modification of the semiconductor deviceshown in FIG. 1.

The semiconductor device 15 shown in FIG. 11 has substantially the samestructure as the semiconductor device 15 shown in FIG. 1. A gateelectrode 31 of the semiconductor device 15 in FIG. 11 includes apoly-Si layer 29 which is lower layer and a W film 30 which is an upperlayer. In such a semiconductor device 15 also, a SiO film 32 and a SiNfilm 33 are sequentially formed after the W film 30 is formed, but ifthe W film 30 is oxidized when the SiO film 32 is formed, there arises aproblem that a shape of the W film 30 is varied due to volume expansioncaused by the oxidation of W. Therefore, when supplying an oxidizingmaterial, the SiO film 32 is formed on the W film 30 by the ALD methodwhile supplying H₂ and preventing the W film from being oxidized.

As explained above, according to the preferred embodiments of thepresent invention, there is provided a producing method of asemiconductor device, comprising: loading at least one substrate formedon a surface thereof with a tungsten film into a processing chamber; andforming a silicon oxide film on the surface of the substrate whichincludes the tungsten film by alternately repeating following steps aplurality of times: supplying the processing chamber with a firstreaction material including a silicon atom while heating the substrateat 400° C.; and supplying the processing chamber with hydrogen and waterwhich is a second reaction material while heating the substrate at 400°C. at a ratio of the water with respect to the hydrogen of 2×10⁻¹ orlower.

According to the preferred embodiments of the present invention, sincewater and hydrogen are supplied into the processing chamber at aspecific ratio, even if the tungsten film is oxidized, its oxide isreduced, and a first reaction material is oxidized even at a lowtemperature as low as 400° C. or less. Therefore, it is possible to forma silicon oxide film on the tungsten film at a low temperature as low as400° C. or less while preventing the tungsten film from being oxidized.

According to the another preferred embodiments of the present invention,there is provided a producing method of a semiconductor device,comprising at least: loading at least one substrate formed on a surfacethereof with a metal film into a processing chamber; and forming anoxide film including silicon on the surface of the substrate whichincludes the metal film, wherein the forming the oxide film includes:supplying a first reaction material including a silicon atom into theprocessing chamber while heating the substrate at a predeterminedtemperature; and supplying hydrogen and a second reaction materialincluding an oxygen atom into the processing chamber while heating thesubstrate at the predetermined temperature.

According to the another preferred embodiments of the present invention,since hydrogen and a second reaction material including an oxygen atomare supplied into the processing chamber, even if the metal film isoxidized, its oxide is reduced, and the first reaction material isoxidized even at a low temperature. Thus, it is possible to form anoxide film on the metal film at a low temperature while preventing themetal film from being oxidized.

Preferably, there is provided a producing method of a semiconductordevice in which in the forming the oxide film, supply of the firstreaction material and supply of the second reaction material and thehydrogen are alternately repeated a plurality of times to form the oxidefilm. An ALD method is used as one example of this producing method.

Preferably, there is provided a producing method of a semiconductordevice in which the metal film is a tungsten film, the predeterminedtemperature is in a range of 100 to 450° C., the second reactionmaterial is water, and when the predetermined temperature and a supplyratio of the water with respect to the hydrogen is defined as (T,H₂O/H₂), the supply ratio of the water with respect to the hydrogen isequal to or less than straight lines connecting points of (T,H₂O/H₂)=(100° C., 8×10⁻⁴), (200° C., 2×10⁻²), (300° C., 9×10⁻²), (400°C., 2×10⁻¹), (450° C., 2.5×10⁻¹).

Preferably, there is provided a producing method of a semiconductordevice in which the metal film is a tungsten film, the predeterminedtemperature is in a range of 100 to 450° C., the second reactionmaterial is ozone, and when the predetermined temperature and a supplyratio of the ozone with respect to the hydrogen is defined as (T,O₃/H₂), the supply ratio of the ozone with respect to the hydrogen isequal to or less than straight lines connecting points of (T,O₃/H₂)=(100° C., 8×10⁻⁴). (200° C., 2×10⁻²), (300° C., 9×10⁻²), (400°C., 2×10⁻¹), (450° C., 2.5×10⁻¹).

Preferably, there is provided a producing method of a semiconductordevice in which in the forming the oxide film, after a thickness of theoxide film reaches a desired thickness, the oxide film is formed withoutsupplying the hydrogen in a supply step of the second reaction materialand the hydrogen.

Preferably, the desired thickness is X₀ defined by the followingequation:

X ₀ =B/A×t,

in which [B/A]=Ce^(−E2/kT), [C]=18.35 Å/second, [E₂]=7.5×10⁻² eV, [k] isa Boltzmann constant and k=8.62×10⁻⁵ eVK⁻¹, and [t] is supply time ofthe second reaction material.

Preferably, there is provided a producing method of a semiconductordevice in which the predetermined temperature is 300° C., the secondreaction material is ozone, in the forming the oxide film, the hydrogenis supplied into the processing chamber in the supply step of the secondreaction material and the hydrogen until a thickness of the oxide filmreaches 20 Å, and after the thickness of the oxide film reaches 20 Å,the oxide film is formed without supplying the hydrogen into theprocessing chamber in the supply step of the second reaction materialand the hydrogen.

Preferably, there is provided a producing method of a semiconductordevice in which in the forming the oxide film, the first reactionmaterial, the second reaction material and the hydrogen are supplied atthe same time to form the oxide film so that the first reactionmaterial, the second reaction material and the hydrogen exist in theprocessing chamber at the same time. A CVD method is used as one exampleof this producing method.

More preferably, there is provided a producing method of a semiconductordevice in which the first reaction material including a silicon atom isan organic compound of silicon such as TDMAS (Tris dimethyl aminosilane).

More preferably, there is provided a producing method of a semiconductordevice in which the second reaction material is an oxidizing materialsuch as water, ozone and oxygen.

More preferably, there is provided a producing method of a semiconductordevice in which when the second reaction material and hydrogen aresupplied, a catalyst such as pyridine is added to form the oxide film.

More preferably, there is provided a producing method of a semiconductordevice in which when the second reaction material and hydrogen aresupplied, plasma excitation is used to excite oxygen as one example ofthe oxidizing material.

More preferably, there is provided a producing method of a semiconductordevice in which an inside of the processing chamber is purged by aninert gas after the supply step of the first reaction material or thesupply step of the second reaction material and hydrogen, and helium(He), neon (Ne), argon (Ar) or nitrogen (N₂) is used as one example ofthe inert gas.

More preferably, there is provided a producing method of a semiconductordevice in which a temperature in the processing chamber is in a range of0 to 700° C.

More preferably, there is provided a producing method of a semiconductordevice in which a pressure in the processing chamber in the forming stepof the oxide film is in a range of 1 to 10000 Pa.

Although various exemplary embodiments have been shown and described,the invention is not limited to the embodiments shown. Therefore, thescope of the invention is intended to be limited solely by the scope ofthe claims that follow.

As explained above, according to the preferred embodiments of thepresent invention, it is possible to form an oxide film on a metal filmat a low temperature while preventing the metal film from beingoxidized. As a result, the present invention can especially suitably beutilized for a producing method of a semiconductor device for forming anoxide film on a substrate formed with a metal film which is a foundationwhile preventing the metal film from being oxidized.

1. A producing method of a semiconductor device, comprising at least:loading at least one substrate formed on a surface thereof with a metalfilm into a processing chamber; and forming an oxide film includingsilicon on the surface of the substrate which includes the metal film;wherein the forming the oxide film includes: supplying a first reactionmaterial including a silicon atom into the processing chamber whileheating the substrate at a predetermined temperature; and supplyinghydrogen and a second reaction material including an oxygen atom intothe processing chamber while heating the substrate at the predeterminedtemperature; wherein in the forming the oxide film, supply of the firstreaction material and supply of the second reaction material and thehydrogen are alternately repeated a plurality of times to form the oxidefilm; wherein the metal film is a tungsten film, the predeterminedtemperature is in a range of 100 to 450° C., the second reactionmaterial is ozone, and when the predetermined temperature and a supplyratio of the ozone with respect to the hydrogen is defined as (T,O₃/H₂), the supply ratio of the ozone with respect to the hydrogen isequal to or less than straight lines connecting points of (T,O₃/H₂)=(100° C., 8×10⁻⁴), (200° C., 2×10⁻²), (300° C., 9×10⁻²), (400°C., 2×10⁻¹), (450° C., 2.5×10⁻¹).
 2. A producing method of asemiconductor device, comprising at least: loading at least onesubstrate formed on a surface thereof with a metal film into aprocessing chamber; and forming an oxide film including silicon on thesurface of the substrate which includes the metal film; wherein theforming the oxide film includes: supplying a first reaction materialincluding a silicon atom into the processing chamber while heating thesubstrate at a predetermined temperature; and supplying hydrogen and asecond reaction material including an oxygen atom into the processingchamber while heating the substrate at the predetermined temperature;wherein in the forming the oxide film, supply of the first reactionmaterial and supply of the second reaction material and the hydrogen arealternately repeated a plurality of times to form the oxide film;wherein in the forming the oxide film, after a thickness of the oxidefilm reaches a desired thickness, the oxide film is formed withoutsupplying the hydrogen in a supply step of the second reaction materialand the hydrogen; wherein the predetermined temperature is 300° C., thesecond reaction material is ozone, in the forming the oxide film, thehydrogen is supplied into the processing chamber in the supply step ofthe second reaction material and the hydrogen until a thickness of theoxide film reaches 20 Å, and after the thickness of the oxide filmreaches 20 Å, the oxide film is formed without supplying the hydrogeninto the processing chamber in the supply step of the second reactionmaterial and the hydrogen.